U.S. patent application number 15/576205 was filed with the patent office on 2018-06-07 for high-viscosity polyester with improved impact properties.
This patent application is currently assigned to Roquette Freres. The applicant listed for this patent is Roquette Freres. Invention is credited to Francoise Fenouillot, Nicolas Jacquel, Jean-Pierre Pascault, Alain Rousseau, Rene Saint-Loup.
Application Number | 20180155493 15/576205 |
Document ID | / |
Family ID | 54186070 |
Filed Date | 2018-06-07 |
United States Patent
Application |
20180155493 |
Kind Code |
A1 |
Jacquel; Nicolas ; et
al. |
June 7, 2018 |
HIGH-VISCOSITY POLYESTER WITH IMPROVED IMPACT PROPERTIES
Abstract
The invention relates to a thermoplastic polymer comprising at
least one 1,4:3,6-dianhydrohexitol unit (A), at least one alicyclic
diol unit (B) other than the 1,4:3,6-dianhydrohexitol units (A) and
at least one high-viscosity terephthalic acid unit (C).
Inventors: |
Jacquel; Nicolas;
(Lambersart, FR) ; Saint-Loup; Rene; (Lomme,
FR) ; Pascault; Jean-Pierre; (Villeurbanne, FR)
; Fenouillot; Francoise; (L'isle D'abeau, FR) ;
Rousseau; Alain; (Saint-Priest, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Roquette Freres |
Lestrem |
|
FR |
|
|
Assignee: |
Roquette Freres
Lestrem
FR
|
Family ID: |
54186070 |
Appl. No.: |
15/576205 |
Filed: |
May 20, 2016 |
PCT Filed: |
May 20, 2016 |
PCT NO: |
PCT/FR2016/051208 |
371 Date: |
November 21, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08G 63/78 20130101;
C08G 63/183 20130101; C08G 63/916 20130101; C08G 63/672 20130101;
C08G 63/80 20130101 |
International
Class: |
C08G 63/80 20060101
C08G063/80; C08G 63/672 20060101 C08G063/672; C08G 63/91 20060101
C08G063/91 |
Foreign Application Data
Date |
Code |
Application Number |
May 22, 2015 |
FR |
1554597 |
Claims
1. A thermoplastic polyester comprising: 1,4:3,6-dianhydrohexitol
units (A); alicyclic diol units (B) other than the
1,4:3,6-dianhydrohexitol units (A); and terephthalic acid units
(C); said polyester not containing any aliphatic non-cyclic diol
units or comprising less than 5 molar % of aliphatic non-cyclic
diol units, relative to all the monomer units of the polyester,
wherein said polyester has a reduced viscosity in solution
(25.degree. C.; phenol (50% m): ortho-dichlorobenzene (50% m); 5 g
polyester/1) of greater than 50 ml/g.
2. The polyester according to claim 1, wherein said reduced
viscosity in solution is greater than 70 ml/g.
3. The polyester according to claim 1, wherein the alicyclic diol
(B) is a diol chosen from 1,4-cyclohexanedimethanol,
1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol or a mixture
of these diols.
4. The polyester according to claim 1, wherein the
1,4:3,6-dianhydrohexitol (A) is isosorbide.
5. The polyester according to claim 1, wherein the polyester does
not contain any aliphatic non-cyclic diol units, or comprises a
molar amount of aliphatic non-cyclic diol units, relative to all
the monomer units of the polyester, of less than 1%.
6. The polyester according to claim 1, wherein the polyester
comprises: a molar amount of 1,4:3,6-dianhydrohexitol units (A)
ranging from greater than 1 to 54%; a molar amount of alicyclic
diol units (B) other than the 1,4:3,6-dianhydrohexitol units (A)
ranging from greater than 1 to 54%; a molar amount of terephthalic
acid units (C) ranging from 45 to 55%.
7. The polyester according to claim 6, comprising: a molar amount
of 1,4:3,6-dianhydrohexitol units (A) ranging from greater than 1
to 20%; a molar amount of alicyclic diol units (B) other than the
1,4:3,6-dianhydrohexitol units (A) ranging from 25 to 54%; a molar
amount of terephthalic acid units (C) ranging from 45 to 55%.
8. The polyester according to claim 1, comprising: a molar amount
of 1,4:3,6-dianhydrohexitol units (A) ranging from 20 to 54%; a
molar amount of alicyclic diol units (B) other than the
1,4:3,6-dianhydrohexitol units (A) ranging from greater than 1 to
35%; a molar amount of terephthalic acid units (C) ranging from 45
to 55%.
9. The polyester according to claim 1, wherein the polyester is
semi-crystalline with a heat of fusion of greater than 10 J/g the
measurement of this heat of fusion consisting in subjecting a
sample of the polyester to a heat treatment at 170.degree. C. for
10 hours, then in evaluating the heat of fusion by DSC by heating
the sample at 10.degree. C./min.
10. The polyester according to claim 1 having an impact strength
greater than 100 kJ/m.sup.2 (25.degree. C., ISO 179-1/1eU:
2010).
11. A process for producing a polyester, comprising: introducing,
into a reactor, monomers comprising 1,4:3,6-dianhydrohexitol (A),
at least one alicyclic diol (B) other than the
1,4:3,6-dianhydrohexitols (A), and terephthalic acid (C), the molar
ratio ((A)+(B))/(C) ranging from 1.05 to 1.5, said monomers not
containing any aliphatic non-cyclic diols or comprising, relative
to all of the monomers introduced, a molar amount of aliphatic
non-cyclic diol units of less than 5%; introducing a catayst into
the reactor; polymerizing said monomers in the presence of the
catalyst to form a polyester comprising: a first stage of
oligomerization, during which the reaction medium is stirred under
an inert atmosphere at a temperature ranging from 265 to
280.degree. C.; a second stage of condensation of the oligomers,
during which the oligomers formed are stirred under vacuum, at a
temperature ranging from 278 to 300.degree. C. so as to form the
polyester; and recovering the polyester.
12. The process for producing the polyester according to claim 11
one of claims 1, further comprising increasing molar mass of said
polyester by post-polymerization with a polymer of lower reduced
viscosity in solution comprising 1,4:3,6-dianhydrohexitol units
(A), alicyclic diol units (B) other than the
1,4:3,6-dianhydrohexitol units (A) and terephthalic acid units (C),
wherein said units (A), (B) and (C) do not contain any aliphatic
non-cyclic diol units or comprises a molar amount of aliphatic
non-cyclic diol units, relative to all of the monomer units of the
polymer, of less than 5%.
13. The process according to claim 12, wherein post-polymerization
step is carried out by solid-state polycondensation (SSP) of the
polymer of lower reduced viscosity in solution.
14. The process as claimed in claim 13, wherein that the SSP is
carried out at a temperature ranging from 190 to 300.degree. C.
15. The process according to claim 12, wherein the polymer of lower
reduced viscosity in solution comprises: a molar amount of
1,4:3,6-dianhydrohexitol units (A) ranging from above 1 to 20%; a
molar amount of alicyclic diol units (B) other than the
1,4:3,6-dianhydrohexitol units (A) ranging from 25 to 54%; a molar
amount of terephthalic acid units (C) ranging from 45 to 55%.
16. The process according to claim 12, wherein the polymer of lower
reduced viscosity in solution is semi-crystalline with a heat of
fusion of greater than 10 J/g, the measurement of this heat of
fusion consisting in subjecting a sample of the polymer of lower
reduced viscosity in solution to a heat treatment at 170.degree. C.
for 10 hours, then in evaluating the heat of fusion by DSC by
heating the sample at 10 K/min.
17. The process according to claim 12, wherein post-polymerization
is carried out by reactive extrusion of the polymer of lower
reduced viscosity in solution in the presence of at least one chain
extender.
18. The process according to claim 17, wherein the chain extender
is chosen from compounds comprising two isocyanate, isocyanurate,
lactam, lactone, carbonate, epoxy, oxazoline and imide functions
according to claim 1, comprising, it being possible for said
functions to be identical or different.
19. A polyester according to claim 11.
20. A polyester composition comprising a polyester according to
claim 11.
21. A plastic article comprising a polyester according to claim 11.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a high-viscosity
thermoplastic polyester comprising at least one
1,4:3,6-dianhydrohexitol unit, which may have excellent impact
strength properties and low coloration. Another subject of the
invention is a process for producing said polyester and the use of
this polyester for producing various articles.
TECHNOLOGICAL BACKGROUND OF THE INVENTION
[0002] Because of their numerous advantages, plastics have become
indispensable in the mass production of objects. Indeed, their
thermoplastic character enables these materials to be transformed
at a high rate into all kinds of objects.
[0003] Certain thermoplastic aromatic polyesters have thermal
properties which allow them to be used directly for the manufacture
of materials. They comprise aliphatic diol and aromatic diacid
units. Among these aromatic polyesters, mention may be made of
polyethylene terephthalate (PET), which is a polyester comprising
ethylene glycol and terephthalic acid units, used for example in
the manufacture of containers, packaging, films or else fibers.
[0004] According to the invention, the term "monomer units" means
units, included in the polyester, which may be obtained after
polymerization of a monomer. With regard to the ethylene glycol and
terephthalic acid units included in PET, they can be obtained
either by esterification reaction of ethylene glycol and
terephthalic acid, or by transesterification reaction of ethylene
glycol and terephthalic acid ester.
[0005] However, for certain applications or under certain usage
conditions, these polyesters do not have all the required
properties, especially optical, impact strength or else heat
resistance properties. This is why glycol-modified PETs (PETgs)
have been developed. They are generally polyesters comprising, in
addition to the ethylene glycol and terephthalic acid units,
cyclohexanedimethanol (CHDM) units. The introduction of this diol
into the PET enables it to adapt the properties to the intended
application, for example to improve its impact strength or its
optical properties, especially when the PETg is amorphous.
[0006] Other modified PETs have also been developed by introducing,
into the polyester, 1,4:3,6-dianhydrohexitol units, especially
isosorbide (PEIT). These modified polyesters have higher glass
transition temperatures than the unmodified PETs or PETgs
comprising CHDM. In addition, 1,4:3,6-dianhydrohexitols have the
advantage of being able to be obtained from renewable resources
such as starch. These modified polyesters are especially useful for
manufacturing bottles, films, thick sheets, fibers or articles
requiring high optical properties.
[0007] However, one problem encountered in the production of
polyesters comprising 1,4:3,6-dianhydrohexitol units, and
especially isosorbide units, is that these polyesters generally
have a coloration. This coloration has been hitherto explained by
the sensitivity of the isosorbide to thermal oxidation at high
temperature. In this regard, reference may be made to the review by
Fenouillot et al., Prog Polym. Sci., 2010, vol 35, page 578 et seq.
which states: "the sensitivity of isosorbide to thermooxidation at
high temperature needed to polymerize polyesters is the cause for
this yellowing". This very high sensitivity of the isosorbide
necessitates, in order to obtain polymers with low coloration,
working in an atmosphere essentially free of dioxygen, with a
generally limited amount of isosorbide and at a lower
temperature.
[0008] In order to deal with this problem, document US2006/0173154
A1 teaches a process which makes it possible to reduce this
phenomenon of coloration of the polyesters linked to the presence
of isosorbide in the starting monomers. This document teaches more
particularly a process for producing
poly(ethylene-co-isosorbide)terephthalate comprising a step of
esterification and a step of polymerization using a
polycondensation catalyst and a secondary antioxidant in determined
proportions. In addition, it is essential that, during this
process, the esterification temperature ranges from 180 to
265.degree. C. and that the polycondensation temperature ranges
from 260 to 275.degree. C.
[0009] An additional problem with polyesters predominantly
comprising ethylene glycol and isosorbide is that they may be
difficult to dry. This means that, during the transformation of the
polyester to the molten state, moisture may cause hydrolysis of
said polyester. Thus, obtaining polyesters which are easier to dry
may make it possible to improve the stability of the polyester
during its transformation in the molten state.
[0010] Another problem with these PEITs is that they may have
insufficient impact strength properties. In addition, the glass
transition temperature may be insufficient for certain
applications.
[0011] In order to improve the impact strength properties of the
polyesters, it is known from the prior art to use polyesters in
which the crystallinity has been reduced. As regards
isosorbide-based polyesters, mention may be made of application
US2012/0177854, which describes polyesters comprising terephthalic
acid units and diol units comprising from 1 to 60 mol % of
isosorbide and from 5 to 99% of 1,4-cyclohexanedimethanol which
have improved impact strength properties. As indicated in the
introductory section of this application, the aim is to obtain
polymers in which the crystallinity is eliminated by the addition
of comonomers, and hence in this case by the addition of
1,4-cyclohexanedimethanol. In the examples part, the manufacture of
various
poly(ethylene-co-1,4-cyclohexanedimethylene-co-isosorbide)terepht-
halates (PECITs), and also an example of
poly(1,4-cyclohexanedimethylene-co-isosorbide)terephthalate (PCIT),
are described.
[0012] However, the Applicant was able to observe (see examples
below) that the PCIT synthesized in this application US2012/0177854
has a reduced viscosity in solution which may be insufficient, for
example, for the manufacture of films when they are produced by
film blowing or else for the manufacture of hollow bodies or
threads. Moreover, although its impact strength is presented as
improved, this is not the case at all for its cold impact strength.
Also, its glass transition temperature may be insufficient for
certain applications (for example for hot-filling). On the
contrary, the PECITs described in this document exhibit much higher
glass transition temperatures. It should be noted that this
document also mentions the phenomenon of coloration of the
polyester linked to the presence of isosorbide in the starting
monomers.
[0013] It may also be noted that while polymers of PECIT type have
been the subject of commercial developments, this is not the case
for PCITs. Indeed, their production was hitherto considered to be
complex, since isosorbide has low reactivity as a secondary diol.
Yoon et al. (Synthesis and Characteristics of a Biobased High-Tg
Terpolyester of Isosorbide, Ethylene Glycol, and 1,4-Cyclohexane
Dimethanol: Effect of Ethylene Glycol as a Chain Linker on
Polymerization, Macromolecules, 2013, 46, 7219-7231) thus showed
that the synthesis of PCIT is much more difficult to achieve than
that of PECIT. This paper describes the study of the influence of
the ethylene glycol content on the PECIT production kinetics.
[0014] In Yoon et al., an amorphous PCIT (which comprises
approximately 29% isosorbide and 71% CHDM, relative to the sum of
the diols) is produced to compare its synthesis and its properties
with those of PECIT-type polymers. The use of high temperatures
during the synthesis induces thermal degradation of the polymer
formed if reference is made to the first paragraph of the Synthesis
section on page 7222, this degradation especially being linked to
the presence of aliphatic cyclic diols such as isosorbide.
Therefore, Yoon et al. used a process in which the polycondensation
temperature is limited to 270.degree. C. Yoon et al. observed that,
even increasing the polymerization time, the process also does not
make it possible to obtain a polyester having a sufficient
viscosity. Thus, without addition of ethylene glycol, the viscosity
of the polyester remains limited, despite the use of prolonged
synthesis times. It should also be noted that, in Yoon et al., the
PCIT obtained is presented as an amorphous polyester.
[0015] To this day there remains a need to find novel thermoplastic
polyesters having a sufficiently high viscosity to be used in more
numerous applications. There is also a need to obtain polymers
which also have low coloration and/or good impact strength
properties, especially in cold conditions.
[0016] In the current state of knowledge, it has hitherto not been
possible to obtain a high-viscosity polyester comprising
1,4:3,6-dianhydrohexitol units (A), alicyclic diol units (B) other
than (A) and terephthalic acid units (C), when this polyester
comprises a low molar amount of aliphatic non-cyclic diol units
such as ethylene glycol. These aliphatic linear diols are
recognized as necessary in the polycondensation reaction to obtain
high-viscosity polymers.
[0017] There is also a preconception about the necessity of using
limited temperatures during processes for producing polyesters
comprising 1,4:3,6-dianhydrohexitol units (A) in order to obtain a
low degradation of the polymer, and therefore a low coloration. To
obtain these polymers, it was necessary to use particular processes
using low esterification and polycondensation temperatures because
of the high sensitivity of the isosorbide to thermal oxidation.
[0018] While conducting studies on the processes for producing
polyesters containing 1,4:3,6-dianhydrohexitol units, the Applicant
has succeeded in obtaining a novel high-viscosity polyester, this
polyester possibly also having excellent impact strength
properties, low coloration and/or an ability to be dried easily.
This polyester may be used under very different temperature
conditions since it has excellent cold impact strength while having
a high glass transition temperature.
SUMMARY OF THE INVENTION
[0019] A subject of the invention is thus a thermoplastic polymer
comprising: [0020] at least one 1,4:3,6-dianhydrohexitol unit (A);
[0021] at least one alicyclic diol unit (B) other than the
1,4:3,6-dianhydrohexitol units (A); [0022] at least one
terephthalic acid unit (C); said polyester not containing any
aliphatic non-cyclic diol units or comprising a molar amount of
aliphatic non-cyclic diol units, relative to all the monomer units
of the polyester, of less than 5%, and the reduced viscosity in
solution (25.degree. C.; phenol (50% m): ortho-dichlorobenzene (50%
m); 5 g polyester/I) of said polyester is greater than 50 ml/g.
[0023] Despite the fact that it may comprise large amounts of
1,4:3,6-dianhydrohexitol units known as agents which generate
coloration in polyesters during polymerization, the Applicant was
able to observe that the polyesters according to the invention
could surprisingly simultaneously exhibit high viscosity and low
coloration.
[0024] This polymer may especially be obtained by a particular
production process, especially comprising a step of introducing,
into a reactor, monomers comprising at least one
1,4:3,6-dianhydrohexitol (A), at least one alicyclic diol (B) other
than the 1,4:3,6-dianhydrohexitols (A) and at least one
terephthalic acid (C), said monomers not containing any aliphatic
non-cyclic diols or comprising a molar amount of aliphatic
non-cyclic diol units of less than 5%, this amount being determined
relative to all the monomers introduced.
[0025] This process comprises a step of polymerization, at a high
temperature, of said monomers to form the polyester, said step
consisting of: [0026] a first stage of oligomerization, during
which the reaction medium is stirred under an inert atmosphere at a
temperature ranging from 265 to 280.degree. C., advantageously from
270 to 280.degree. C., for example 275.degree. C.; [0027] a second
stage of condensation of the oligomers, during which the oligomers
formed are stirred under vacuum, at a temperature ranging from 278
to 300.degree. C. so as to form the polyester, advantageously from
280 to 290.degree. C., for example 285.degree. C.; [0028] a step of
recovering the polyester; in which the molar ratio ((A)+(B))/(C)
ranges from 1.05 to 1.5.
[0029] The Applicant observed that, by using a terephthalic acid as
monomer (C), very specific selected amounts of (A), (B) and (C) and
high temperatures during polymerization (oligomerization and
condensation of the oligomers), it is entirely possible to obtain
novel polyesters having a higher viscosity. Contrary to what was
believed by those skilled in the art, the 1.4:3,6-dianhydrohexitols
(and in particular isosorbide) as the only diols are not
responsible for the coloration of the polyesters during the
polymerization, despite the high temperatures used during the
process. The Applicant has surprisingly found that the polyesters
only become colored if the diols used are mixtures of
1.4:3,6-dianhydrohexitols with aliphatic non-cyclic diols, and in
particular when the molar amount of aliphatic non-cyclic diols is
equal to or exceeds 5%. Without being bound by a particular theory,
it appears that the degradation of 1,4:3,6-dianhydrohexitols is
increased during polymerization when aliphatic non-cyclic diols are
included in the starting monomers. This could be explained by the
fact that these aliphatic non-cyclic diols polymerize rapidly with
terephthalic acid, which would slow down the polymerization of the
1,4:3,6-dianhydrohexitols with the terephthalic acid; the
1.4:3,6-dianhydrohexitols would then be subjected to high
temperatures for a longer period, which would induce a phenomenon
of high coloration of the polyester and a reduction in the
viscosity of the polyester formed.
[0030] The polyester according to the invention has a high reduced
viscosity in solution and can be used in many plastics
transformation tools, and especially be easily transformed by blow
molding. It also has excellent impact strength properties.
According to certain embodiments of the invention, they may also
have particularly high glass transition temperatures.
[0031] Another subject of the invention is various processes for
producing this polyester.
DETAILED DESCRIPTION OF THE INVENTION
[0032] The polymer which is a subject of the invention is a
thermoplastic polyester comprising: [0033] at least one
1,4:3,6-dianhydrohexitol unit (A); [0034] at least one alicyclic
diol unit (B) other than the 1,4:3,6-dianhydrohexitol units (A);
[0035] at least one terephthalic acid unit (C).
[0036] The polyester according to the invention does not contain
any aliphatic non-cyclic diol units, or comprises a small amount
thereof.
[0037] "Low molar amount of aliphatic non-cyclic diol units" is
intended to mean, especially, a molar amount of aliphatic
non-cyclic diol units of less than 5%. According to the invention,
this molar amount represents the ratio of the sum of the aliphatic
non-cyclic diol units, these units possibly being identical or
different, relative to all the monomer units of the polyester.
[0038] An aliphatic non-cyclic diol may be a linear or branched
aliphatic non-cyclic diol. It may also be a saturated or
unsaturated aliphatic non-cyclic diol. Aside from ethylene glycol,
the saturated linear aliphatic non-cyclic diol may for example be
1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol,
1,8-octanediol and/or 1,10-decanediol. As examples of saturated
branched aliphatic non-cyclic diol, mention may be made of
2-methyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol,
2-ethyl-2-butyl-1,3-propanediol, propylene glycol and/or neopentyl
glycol. As an example of an unsaturated aliphatic diol, mention may
be made, for example, of cis-2-butene-1,4-diol.
[0039] This molar amount of aliphatic non-cyclic diol units is
advantageously less than 1%. Preferably, the polyester does not
contain any aliphatic non-cyclic diol units.
[0040] Despite the small amount of aliphatic non-cyclic diol, and
hence ethylene glycol, used for producing the polyester, the
polyester has a high reduced viscosity in solution.
[0041] This high reduced viscosity in solution enables the
polyester to be able to be used in numerous applications described
below.
[0042] This reduced viscosity in solution may be greater than 50
ml/g, this viscosity being able to be measured using an Ubbelohde
capillary viscosimeter at 25.degree. C. in an equi-mass mixture of
phenol and ortho-dichlorobenzene after dissolving the polymer at
130.degree. C. with stirring, the concentration of polymer
introduced being 5 g/l.
[0043] This test for measuring reduced viscosity in solution is,
due to the choice of solvents and the concentration of the polymers
used, perfectly suited to determining the viscosity of the viscous
polymer of the present invention. According to the present
invention, a polyester of reduced viscosity in solution of greater
than 50 ml/g and extending up to 70 ml/g is considered to be a
"high-viscosity polyester".
[0044] The Applicant has also succeeded in obtaining a polyester
having an even higher viscosity, hereinafter referred to as "very
high-viscosity polyester". "Very high-viscosity polyester" is
intended to mean, according to the invention, a polyester having a
reduced viscosity in solution of greater than 70 ml/g,
advantageously greater than 75 ml/g, preferably greater than 85
ml/g, most preferentially greater than 95 ml/g.
[0045] In the case where the polyester according to the invention
is a very high-viscosity polyester, it has excellent impact
strength properties at room temperature but also good cold impact
strength properties. Since this polyester can be used and
mechanically stressed at low temperature, this enables it to be
used in numerous applications, in various industries such as, for
example, the automotive or household appliance industries.
[0046] The monomer (A) is a 1,4:3,6-dianhydrohexitol. As explained
previously, 1,4:3,6-dianhydrohexitols have the drawback of being
secondary diols which are not very reactive in the production of
polyesters. The 1,4:3,6-dianhydrohexitol (A) may be isosorbide,
isomannide, isoidide, or a mixture thereof. Preferably, the
1,4:3,6-dianhydrohexitol (A) is isosorbide.
[0047] Isosorbide, isomannide and isoidide may be obtained,
respectively, by dehydration of sorbitol, of mannitol and of
iditol. As regards isosorbide, it is sold by the Applicant under
the brand name Polysorb.RTM. P.
[0048] The alicyclic diol (B) is also referred to as aliphatic
cyclic diol. It is a diol which may especially be chosen from
1,4-cyclohexanedimethanol, 1,2-cyclohexanedimethanol,
1,3-cyclohexanedimethanol or a mixture of these diols. The
alicyclic diol (B) is very preferentially
1,4-cyclohexanedimethanol. The alicyclic diol (B) may be in the cis
configuration, in the trans configuration, or may be a mixture of
diols in the cis and trans configurations.
[0049] The polyester of the invention may for example comprise:
[0050] a molar amount of 1,4:3,6-dianhydrohexitol units (A) ranging
from 1 to 54%; [0051] a molar amount of alicyclic diol units (B)
other than the 1,4:3,6-dianhydrohexitol units (A) ranging from 1 to
54%; [0052] a molar amount of terephthalic acid units (C) ranging
from 45 to 55%.
[0053] The amounts of different units in the polyester may be
determined by .sup.1H NMR or by chromatographic analysis of the
mixture of monomers resulting from complete hydrolysis or
methanolysis of the polyester, preferably by .sup.1H NMR.
[0054] Those skilled in the art can easily find the analysis
conditions for determining the amounts of each of the units of the
polyester. For example, from an NMR spectrum of a
poly(1,4-cyclohexanedimethylene-co-isosorbide terephthalate), the
chemical shifts relating to the 1,4-cyclohexanedimethanol are
between 0.9 and 2.4 ppm and 4.0 and 4.5 ppm, the chemical shifts
relating to the terephthalate ring are between 7.8 and 8.4 ppm and
the chemical shifts relating to the isosorbide are between 4.1 and
5.8 ppm. The integration of each signal makes it possible to
determine the amount of each unit of the polyester.
[0055] The polyester according to the invention may be
semi-crystalline or amorphous. The semi-crystalline character of
the polymer depends primarily on the amounts of each of the units
in the polymer. Thus, when the polymer according to the invention
comprises large amounts of 1,4:3,6-dianhydrohexitol units (A), the
polymer is generally amorphous, whereas it is generally
semi-crystalline in the opposite case.
[0056] Preferably, the polyester according to the invention has a
glass transition temperature ranging from 85 to 200.degree. C.
[0057] According to one advantageous embodiment, the polyester
according to the invention comprises: [0058] a molar amount of
1,4:3,6-dianhydrohexitol units (A) ranging from 1 to 20%,
advantageously from 5 to 15%; [0059] a molar amount of alicyclic
diol units (B) other than the 1,4:3,6-dianhydrohexitol units (A)
ranging from 25 to 54%, advantageously from 30 to 50%; [0060] a
molar amount of terephthalic acid units (C) ranging from 45 to
55%.
[0061] According to this advantageous embodiment, the polyester is
generally semi-crystalline. The Applicant has succeeded in
obtaining polyesters having semi-crystalline properties, even when
the molar amount of 1,4:3,6-dianhydrohexitols reaches 20%. This
polyester surprisingly exhibits excellent impact strength
properties. Moreover, the crystallization rate of these novel
polyesters is greater than that of PEITs and PEICTs, which makes it
possible to transform them into articles having improved
application properties. In particular, this semi-crystalline
polyester has a particularly high thermomechanical strength, due to
its high glass transition temperature and the presence of
crystallinity which reinforces the mechanical properties at high
temperature.
[0062] Preferably, when the polyester according to the invention is
semi-crystalline, it has a melting point ranging from 210 to
295.degree. C., for example from 240 to 285.degree. C.
[0063] Preferably, when the polyester according to the invention is
semi-crystalline, it has a glass transition temperature ranging
from 85 to 140.degree. C., for example from 90 to 115.degree.
C.
[0064] The glass transition temperatures and melting points are
measured by conventional methods, especially using differential
scanning calorimetry (DSC) using a heating rate of 10.degree.
C./min. The experimental protocol is described in detail in the
example section below.
[0065] Advantageously, when the polyester according to the
invention is semi-crystalline, it has a heat of fusion of greater
than 10 J/g, preferably greater than 30 J/g, the measurement of
this heat of fusion consisting in subjecting a sample of this
polyester to a heat treatment at 170.degree. C. for 10 hours, then
in evaluating the heat of fusion by DSC by heating the sample at
10.degree. C./min.
[0066] According to another embodiment of the invention, the
polyester comprises: [0067] a molar amount of
1,4:3,6-dianhydrohexitol units (A) ranging from 20 to 54%; [0068] a
molar amount of alicyclic diol units (B) other than the
1,4:3,6-dianhydrohexitol units (A) ranging from 1 to 35%; [0069] a
molar amount of terephthalic acid units (C) ranging from 45 to
55%.
[0070] According to this other embodiment, the polymer is generally
amorphous.
[0071] Preferably, when the polyester according to the invention is
amorphous, it has a glass transition temperature ranging from 120
to 200.degree. C., for example from 140 to 190.degree. C.
[0072] The polyester according to the invention may have low
coloration and especially have a lightness L* greater than 50.
Advantageously, the lightness L* is greater than 55, preferably
greater than 60, most preferentially greater than 65, for example
greater than 70.
[0073] The parameters L* may be determined using a
spectrophotometer, via the CIE Lab model.
[0074] The polyester according to the invention, especially that of
very high viscosity, has a very good impact strength, in particular
a very good cold impact strength.
[0075] The polyester according to the invention, especially that of
very high viscosity, advantageously has a non-notched Charpy impact
strength greater than 100 kJ/m.sup.2 (25.degree. C., ISO 179-1/1eU:
2010).
[0076] The polyester according to the invention, especially that of
very high viscosity, advantageously has a notched Charpy impact
strength greater than 5 kJ/m.sup.2, advantageously greater than 10
kJ/m.sup.2 (-30.degree. C., ISO 179-1/1eA : 2010).
[0077] These very high impact strength properties were able to be
obtained even when the polyester according to the invention is
semi-crystalline. This goes against the teaching of application
US2012/0177854, which teaches decreasing the crystallinity of the
polyester with a view to improving the impact strength properties
thereof.
[0078] Another subject of the invention is a process for producing
the polyester according to the invention.
[0079] According to a first variant of the process of the
invention, the Applicant has succeeded in obtaining a polyester,
which may have a high reduced viscosity in solution, by a
production process comprising: [0080] a step of introducing, into a
reactor, monomers comprising at least one 1,4:3,6-dianhydrohexitol
(A), at least one alicyclic diol (B) other than the
1,4:3,6-dianhydrohexitols (A) and at least one terephthalic acid
(C), the molar ratio ((A) +(B))/(C) ranging from 1.05 to 1.5, said
monomers not containing any aliphatic non-cyclic diols or
comprising, relative to all of the monomers introduced, a molar
amount of aliphatic non-cyclic diol units of less than 5%; [0081] a
step of introducing, into the reactor, a catalytic system; [0082] a
step of polymerizing said monomers to form the polyester, said step
consisting of: [0083] a first stage of oligomerization, during
which the reaction medium is stirred under an inert atmosphere at a
temperature ranging from 265 to 280.degree. C., advantageously from
270 to 280.degree. C., for example 275.degree. C.; [0084] a second
stage of condensation of the oligomers, during which the oligomers
formed are stirred under vacuum, at a temperature ranging from 278
to 300.degree. C. so as to form the polyester, advantageously from
280 to 290.degree. C., for example 285.degree. C.; [0085] a step of
recovering the polyester.
[0086] Thus, contrary to that which was expected due to the use of
high temperatures during the stages of oligomerization and
condensation of the oligomers, it is entirely possible, using the
first variant of the process according to the invention, to obtain
high-viscosity polyesters with low coloration. Without being bound
by any theory, the Applicant explains this low coloration by the
fact that it is only when large amounts of aliphatic non-cyclic
diol are used in combination with 1,4:3,6-dianhydrohexitol that the
latter degrades in the reactor during polymerization. Quite
unexpectedly, according to the process of the invention which uses
small molar amounts of aliphatic non-cyclic diol (less than 5%), or
even does not use this monomer, it is entirely possible to obtain
polymers simultaneously exhibiting high viscosity and low
coloration.
[0087] The polymer obtained may thus at least have a reduced
viscosity in solution of greater than 50 ml/g.
[0088] This first stage of this variant of the process is carried
out in an inert atmosphere, that is to say under an atmosphere of
at least one inert gas. This inert gas may especially be
dinitrogen. This first stage can be carried out under a gas stream.
It can also be carried out under pressure, for example at a
pressure of between 1.05 and 8 bar.
[0089] Preferably, the pressure ranges from 3 to 8 bar, most
preferentially from 5 to 7.5 bar, for example 6.6 bar. Under these
preferred pressure conditions, the reaction of all the monomers
with one another is promoted by limiting the loss of monomers
during this stage.
[0090] Prior to the first stage of oligomerization, a step of
deoxygenation of the monomers is preferentially carried out. It can
be carried out for example by generating a vacuum after having
introduced the monomers into the reactor and then by introducing an
inert gas such as nitrogen into the reactor. This vacuum-inert gas
introduction cycle can be repeated several times, for example from
3 to 5 times. Preferably, this vacuum-nitrogen cycle is carried out
at a temperature of between 60 and 80.degree. C. so that the
reagents, and especially the diols, are totally molten. This
deoxygenation step has the advantage of improving the coloration
properties of the polyester obtained at the end of the process.
[0091] The second stage of condensation of the oligomers is carried
out under vacuum. The pressure may decrease continuously during
this second stage by using pressure decrease ramps, in steps, or
else using a combination of pressure decrease ramps and steps.
Preferably, at the end of this second stage, the pressure is less
than 10 mbar, most preferentially less than 1 mbar.
[0092] According to this first variant of the process, the first
stage of the polymerization step preferably has a duration ranging
from 20 minutes to 5 hours. Advantageously, the second stage has a
duration ranging from 30 minutes to 6 hours, the beginning of this
stage being the moment at which the reactor is placed under vacuum,
that is to say at a pressure of less than 1 bar.
[0093] The process of this first variant comprises a step of
introducing a catalytic system into the reactor. This step may take
place beforehand or during the polymerization step described
above.
[0094] Catalytic system is intended to mean a catalyst or a mixture
of catalysts, optionally dispersed or fixed on an inert
support.
[0095] The catalyst is used in amounts suitable for obtaining a
high-viscosity polymer in accordance with the invention.
[0096] An esterification catalyst is advantageously used during the
oligomerization stage. This esterification catalyst can be chosen
from tin derivatives, titanium derivatives, zirconium derivatives,
hafnium derivatives, zinc derivatives, manganese derivatives,
calcium derivatives and strontium derivatives, organic catalysts
such as para-toluenesulfonic acid (PTSA) or methanesulfonic acid
(MSA), or a mixture of these catalysts. By way of example of such
compounds, mention may be made of those given in application US
2011282020A1 in paragraphs [0026] to [0029], and on page 5 of
application WO 2013/062408 A1.
[0097] Preferably, a titanium derivative, a zinc derivative or a
manganese derivative is used during the first stage of
transesterification.
[0098] By way of example of amounts by weight, use may be made of
from 10 to 500 ppm of catalytic system during the oligomerization
stage, relative to the amount of monomers introduced.
[0099] At the end of transesterification, the catalyst from the
first step can be optionally blocked by adding phosphorous acid or
phosphoric acid, or else, as in the case of tin(IV), reduced with
phosphites such as triphenyl phosphite or tris(nonylphenyl)
phosphites or those cited in paragraph [0034] of application US
2011 282020A1.
[0100] The second stage of condensation of the oligomers may
optionally be carried out with the addition of a catalyst. This
catalyst is advantageously chosen from tin derivatives,
preferentially derivatives of tin, titanium, zirconium, germanium,
antimony, bismuth, hafnium, magnesium, cerium, zinc, cobalt, iron,
manganese, calcium, strontium, sodium, potassium, aluminum or
lithium, or of a mixture of these catalysts. Examples of such
compounds may for example be those given in patent EP 1 882 712 B1
in paragraphs [0090] to [0094].
[0101] Preferably, the catalyst is a tin, titanium, germanium,
aluminum or antimony derivative.
[0102] By way of example of amounts by weight, use may be made of
from 10 to 500 ppm of catalytic system during the stage of
condensation of the oligomers, relative to the amount of monomers
introduced.
[0103] Preferably, a catalytic system is used during the first
stage and the second stage of polymerization. Said system
advantageously consists of a catalyst based on tin or of a mixture
of catalysts based on tin, titanium, germanium and aluminum.
[0104] By way of example, use may be made of an amount by weight of
10 to 500 ppm of catalytic system relative to the amount of
monomers introduced.
[0105] According to the process of the first variant, an
antioxidant is advantageously used during the step of
polymerization of the monomers. These antioxidants make it possible
to reduce the coloration of the polyester obtained. The
antioxidants may be primary and/or secondary antioxidants. The
primary antioxidant may be a sterically hindered phenol, such as
the compounds Hostanox.RTM. 0 3, Hostanox.RTM. 0 10, Hostanox.RTM.
0 16, Ultranox.RTM. 210, Ultranox.RTM. 276, Dovernox.RTM. 10,
Dovernox.RTM. 76, Dovernox.RTM. 3114, Irganox.RTM. 1010 or
Irganox.RTM. 1076 or a phosphonate such as Irgamod.RTM. 195. The
secondary antioxidant may be trivalent phosphorus compounds such as
Ultranox.RTM. 626, Doverphos.RTM. S-9228, Hostanox.RTM. P-EPQ or
Irgafos 168.
[0106] It is also possible to introduce as polymerization additive
into the reactor at least one compound that is capable of limiting
spurious etherification reactions, such as sodium acetate,
tetramethylammonium hydroxide or tetraethylammonium hydroxide.
[0107] The process of the first variant comprises a step of
recovering the polyester at the end of the polymerization step. The
polyester can be recovered by extracting it from the reactor in the
form of a molten polymer rod. This rod can be converted into
granules using conventional granulation techniques.
[0108] The polyester thus recovered has a reduced viscosity in
solution of greater than 50 ml/g and generally less than 70
ml/g.
[0109] According to a second variant of the process of the
invention, the process for producing the polyester comprises a step
of increasing the molar mass by post-polymerization of a polymer of
lower reduced viscosity in solution, which comprises at least one
1,4:3,6-dianhydrohexitol unit (A), at least one alicyclic diol unit
(B) other than the 1,4:3,6-dianhydrohexitol units (A) and at least
one terephthalic acid unit (C), said polymer of lower reduced
viscosity in solution not containing any aliphatic non-cyclic diol
units or comprising a molar amount of aliphatic non-cyclic diol
units, relative to all of the monomer units of the polymer, of less
than 5%.
[0110] According to this second advantageous variant of the
invention, it is possible to obtain a polyester having a
particularly high reduced viscosity in solution, for example
greater than 70 ml/g.
[0111] "Polymer of lower reduced viscosity in solution" is intended
to mean a polyester having a reduced viscosity in solution which is
lower than that of the polyester obtained at the end of the
post-polymerization step. This polymer can be obtained according to
the methods described in the documents US2012/0177854 and Yoon et
al., using production processes using diols and diesters of
terephthalic acid as monomers, or using the process of the first
variant described above.
[0112] The post-polymerization step may consist of a step of
solid-state polycondensation (SSP) of the polymer of lower reduced
viscosity in solution or of a step of reactive extrusion of the
polymer of lower reduced viscosity in solution in the presence of
at least one chain extender.
[0113] According to a first particularly preferred embodiment of
this second variant of the process, this post-polymerization step
is carried out by SSP.
[0114] SSP is generally carried out at a temperature between the
glass transition temperature and the melting point of the polymer.
Thus, in order to carry out the SSP, it is necessary that the
polymer of lower reduced viscosity in solution is semi-crystalline.
Preferably the latter has a heat of fusion of greater than 10 J/g,
preferably greater than 30 J/g, the measurement of this heat of
fusion consisting in subjecting a sample of this polymer of lower
reduced viscosity in solution to a heat treatment at 170.degree. C.
for 10 hours, then in evaluating the heat of fusion by DSC by
heating the sample at 10 K/min.
[0115] Preferably, the polymer of lower reduced viscosity in
solution comprises: [0116] a molar amount of
1,4:3,6-dianhydrohexitol units (A) ranging from 1 to 20%,
advantageously from 5 to 15%; [0117] a molar amount of alicyclic
diol units (B) other than the 1,4:3,6-dianhydrohexitol units (A)
ranging from 25 to 54%, advantageously from 30 to 50%; [0118] a
molar amount of terephthalic acid units (C) ranging from 45 to
55%.
[0119] Advantageously, according to this embodiment of the process,
the SSP step is carried out at a temperature ranging from 190 to
300.degree. C., preferably from 200 to 280.degree. C.
[0120] The SSP step may be carried out in an inert atmosphere, for
example under nitrogen or under argon or under vacuum.
[0121] According to a second embodiment of the process of the
invention, the post-polymerization step is carried out by reactive
extrusion of the polymer of lower reduced viscosity in solution in
the presence of at least one chain extender.
[0122] The chain extender is a compound comprising two functions
capable of reacting, in reactive extrusion, with alcohol,
carboxylic acid and/or carboxylic acid ester functions of the
polymer of lower reduced viscosity in solution. The chain extender
may, for example, be chosen from compounds comprising two
isocyanate, isocyanurate, lactam, lactone, carbonate, epoxy,
oxazoline and imide functions, it being possible for said functions
to be identical or different.
[0123] The reactive extrusion may be carried out in an extruder of
any type, especially a single-screw extruder, a co-rotating
twin-screw extruder or a counter-rotating twin-screw extruder.
However, it is preferred to carry out this reactive extrusion using
a co-rotating extruder.
[0124] The reactive extrusion step may be carried out by: [0125]
introducing the polymer of lower reduced viscosity in solution into
the extruder so as to melt said polymer; [0126] then introducing
the chain extender into the molten polymer; [0127] then reacting
the polymer with the chain extender in the extruder; [0128] then
recovering the polyester obtained in the extrusion step.
[0129] During extrusion, the temperature inside the extruder is
regulated so as to be at a temperature above the glass transition
temperature if the polymer is amorphous and above the melting point
if the polymer is semi-crystalline. The temperature inside the
extruder may range from 150 to 320.degree. C.
[0130] The invention also relates to the polyester able to be
obtained by the process of the invention.
[0131] The invention also relates to a composition comprising the
polyester according to the invention, this composition possibly
comprising at least one additive or at least one additional polymer
or at least one mixture thereof.
[0132] The polyester composition according to the invention may
comprise the polymerization additives optionally used during the
process. It may also comprise other additives and/or additional
polymers that are generally added during a subsequent
thermomechanical mixing step.
[0133] By way of examples of additives, mention may be made of
fillers or fibers of organic or mineral, nanometric or
non-nanometric, functionalized or non-functionalized nature. They
may be silicas, zeolites, glass fibers or beads, clays, mica,
titanates, silicates, graphite, calcium carbonate, carbon
nanotubes, wood fibers, carbon fibers, polymer fibers, proteins,
cellulose-based fibers, lignocellulosic fibers and non-destructured
granular starch. These fillers or fibers can make it possible to
improve the hardness, the rigidity or the water- or
gas-permeability. The composition may comprise from 0.1% to 75% by
weight of fillers and/or fibers relative to the total weight of the
composition, for example from 0.5% to 50%. The additive that is of
use in the composition according to the invention may also comprise
opacifiers, dyes and pigments. They may be chosen from cobalt
acetate and the following compounds: HS-325 Sandoplast.RTM. Red BB
(which is a compound bearing an azo function, also known under the
name Solvent Red 195), HS-510 Sandoplast.RTM. Blue 2B which is an
anthraquinone, Polysynthren.RTM. Blue R, and Clariant.RTM. RSB
Violet.
[0134] The composition may also comprise, as additive, a processing
aid, for reducing the pressure in the processing tool. A demolding
agent which makes it possible to reduce the adhesion to the
materials for forming the polyester, such as the molds or the
calendering rollers, may also be used. These aids may be chosen
from fatty acid esters and fatty acid amides, metal salts, soaps,
paraffins and hydrocarbon-based waxes. Particular examples of these
agents are zinc stearate, calcium stearate, aluminum stearate,
stearamides, erucamides, behenamides, beeswaxes or candelilla
wax.
[0135] The composition according to the invention may also comprise
other additives, such as stabilizers, for example light
stabilizers, UV stabilizers and heat stabilizers, fluidizers, flame
retardants and antistatic agents.
[0136] The composition may also comprise an additional polymer
other than the polyester according to the invention. This polymer
may be chosen from polyamides, polyesters other than the polyester
according to the invention, polystyrene, styrene copolymers,
styrene-acrylonitrile copolymers, styrene-acrylonitrile-butadiene
copolymers, poly(methyl methacrylate)s, acrylic copolymers,
poly(ether-imide)s, poly(phenylene oxide)s, such as
poly(2,6-dimethylphenylene oxide), poly(phenylene sulfate)s,
poly(ester-carbonate)s, polycarbonates, polysulfones, polysulfone
ethers, polyether ketones, and mixtures of these polymers.
[0137] The composition may also comprise, as additional polymer, a
polymer which makes it possible to improve the impact properties of
the polymer, especially functional polyolefins such as
functionalized ethylene or propylene polymers and copolymers,
core-shell copolymers or block copolymers.
[0138] The composition according to the invention may also comprise
polymers of natural origin, such as starch, cellulose, chitosans,
alginates, proteins such as gluten, pea proteins, casein, collagen,
gelatin or lignin, these polymers of natural origin possibly being
physically or chemically modified.
[0139] The starch may be used in destructured or plasticized form.
In the latter case, the plasticizer may be water or a polyol,
especially glycerol, polyglycerol, isosorbide, sorbitans, sorbitol,
mannitol or else urea. The process described in document WO
2010/010 282 A1 may especially be used to prepare the
composition.
[0140] The composition according to the invention may be produced
by conventional thermoplastics mixing methods. These conventional
methods comprise at least one step of mixing the polymers in the
molten or softened state and a step of recovering the composition.
This process may be performed in paddle or rotor internal mixers,
external mixers, or single-screw or twin-screw co-rotating or
counter-rotating extruders. However, it is preferred to produce
this mixture by extrusion, especially using a co-rotating
extruder.
[0141] The mixing of the constituents of the composition may take
place under an inert atmosphere.
[0142] In the case of an extruder, the various constituents of the
composition may be introduced by means of feed hoppers located
along the extruder.
[0143] The invention also relates to a plastic, finished or
semi-finished article comprising the polyester or the composition
according to the invention.
[0144] This article may be of any type and may be obtained using
conventional transformation techniques.
[0145] It may be, for example, fibers or threads that are of use in
the textile industry or other industries. These fibers or threads
may be woven so as to form fabrics, or else nonwovens.
[0146] The article according to the invention may also be a film or
a sheet. These films or sheets may be manufactured by the
techniques of calendering, extrusion film cast, extrusion film
blowing, followed or not by monoaxial or polyaxial stretching or
orientation techniques. These sheets may be thermoformed or
injected to be used, for example, for parts such as the viewing
windows or covers for machines, the body of various electronic
devices (telephones, computers, screens) or else as
impact-resistant windows.
[0147] The article may also be transformed also be processed by
extrusion of profiled elements which may have applications in the
building and construction sectors.
[0148] The article according to the invention may also be a
container for transporting gases, liquids and/or solids. The
containers concerned may be baby bottles, flasks, bottles, for
example sparkling or still water bottles, juice bottles, soda
bottles, carboys, alcoholic drink bottles, small bottles, for
example small medicine bottles, small bottles for cosmetic
products, these small bottles possibly being aerosols, dishes, for
example for ready meals, microwave dishes, or else lids. These
containers may be of any size. They may be produced by extrusion
blow molding, thermoforming or injection blow molding.
[0149] These articles may also be optical articles, i.e. articles
requiring good optical properties, such as lenses, disks,
transparent or translucent panels, light-emitting diode (LED)
components, optical fibers, films for LCD screens or else windows.
These optical articles have the advantage of being able to be
placed close to light sources and therefore to heat sources, while
retaining excellent dimensional stability and good resistance to
light.
[0150] Among the applications of the article, mention may also be
made of parts with a protective aim where impact strength is
important, such as cell phone protectors, spherical packaging, but
also, in the automotive sector, bumpers and dashboard elements.
[0151] The articles may also be multilayer articles, at least one
layer of which comprises the polymer or the composition according
to the invention. These articles may be produced via a process
comprising a coextrusion step in the case where the materials of
the various layers are placed in contact in the molten state. By
way of example, mention may be made of the techniques of tube
coextrusion, profile coextrusion, coextrusion blow molding of a
bottle, a small bottle or a tank, generally collated under the term
"coextrusion blow molding of hollow bodies", coextrusion blow
molding, also known as film blowing, and cast coextrusion.
[0152] They may also be produced according to a process comprising
a step of applying a layer of molten polyester onto a layer based
on organic polymer, metal or adhesive composition in the solid
state. This step may be performed by pressing, by overmolding,
stratification or lamination, extrusion-lamination, coating,
extrusion-coating or spreading.
[0153] The invention will now be illustrated in the examples below.
It is specified that these examples do not in any way limit the
present invention.
EXAMPLES
[0154] The properties of the polymers were studied via the
following techniques:
[0155] The reduced viscosity in solution is evaluated using an
Ubbelohde capillary viscometer at 25.degree. C. in an equi-mass
mixture of phenol and ortho-dichlorobenzene after dissolving the
polymer at 130.degree. C. with magnetic stirring. For these
measurements, the polymer concentration introduced is 5 g/l.
[0156] The color of the polymer was measured on the granules (25
grams of granules in the measuring cell) using a Konica Minolta
CM-2300d spectrophotometer.
[0157] The mechanical properties of the polymers were evaluated
according to the following standards:
Bending test: ISO 178 Tensile test: ISO 527 Charpy impact test: ISO
179-1: 2010 (non-notched: ISO 179-1/1eU, notched: EN ISO
179-1/1eA)
[0158] The impact strengths were determined as follows: [0159] in a
first step, the test according to standard ISO 179-1 1eU is carried
out at 25.degree. C.; [0160] if, during this first test, the
strength is greater than 155 kJ/m.sup.2, the ISO 179-1/1eA test is
carried out at 25.degree. C.; [0161] if, during this second test,
the strength is greater than 155 kJ/m.sup.2, the ISO 179-1/1eA test
is carried out at -30.degree. C. HDT test, Method B, stress 0.45
MPa ISO 75
Vicat Method B50 ISO 306
DSC
[0162] The thermal properties of the polyesters were measured by
differential scanning calorimetry (DSC): The sample is first heated
under a nitrogen atmosphere in an open crucible from 10.degree. C.
to 320.degree. C. (10.degree. C. min.sup.-1), cooled to 10.degree.
C. (10.degree. C. min.sup.-1), then heated again to 320.degree. C.
under the same conditions as the first step. The glass transition
temperatures were taken at the mid-point of the second heating. Any
melting points are determined on the endothermic peak (onset) at
the first heating. Similarly, the enthalpy of fusion (area under
the curve) is determined at the first heating.
[0163] For the illustrative examples presented below, the following
reagents were used:
Ethylene glycol (purity >99.8%) from Sigma-Aldrich
1,4-Cyclohexanedimethanol (99% purity, mixture of cis and trans
isomers) Isosorbide (purity >99.5%) Polysorb.RTM. P from
Roquette Freres Terephthalic acid (99+% purity) from Acros
Germanium dioxide (>99.99%) from Sigma-Aldrich Irgamod 1010 from
BASF AG Dibutyltin oxide (98% purity) from Sigma-Aldrich
Carbonylbiscaprolactam (Allinco CBC) from DSM. Tritan TX2001:
performance copolyester sold by Eastman.RTM.
Preparation of the Polyesters
Example 1
[0164] 1680 g (11.6 mol) of 1,4-cyclohexanedimethanol, 233 g (1.6
mol) of isosorbide, 2000 g (12.0 mol) of terephthalic acid, 1.65 g
of Irganox 1010 (antioxidant) and 1.39 g of dibutyltin oxide
(catalyst) are added to a 7.5 I reactor. To extract the residual
oxygen from the isosorbide crystals, four vacuum-nitrogen cycles
are performed once the temperature of the reaction medium is
between 60 and 80.degree. C. The reaction mixture is then heated to
275.degree. C. (4.degree. C./min) under 6.6 bar of pressure and
with constant stirring (150 rpm). The degree of esterification is
estimated from the amount of distillate collected. The pressure is
then reduced to 0.7 mbar over 90 minutes following a logarithmic
ramp and the temperature is brought to 285.degree. C. These vacuum
and temperature conditions were maintained until an increase in
torque of 15 Nm relative to the initial torque was obtained.
Finally, a polymer rod is cast via the bottom valve of the reactor,
cooled to 15.degree. C. in a heat-regulated water bath and chopped
in the form of granules of about 15 mg.
[0165] The resin thus obtained has a reduced viscosity in solution
of 69.9 ml/g.sup.-1. .sup.1H NMR analysis of the polyester shows
that the final polyester contains 3.2 mol % of isosorbide relative
to all the monomer units. With regard to the thermal properties
(measured at the second heating), the polymer has a glass
transition temperature of 91.degree. C., a melting point of
276.degree. C. with an enthalpy of fusion of 44.5 J/g. The
mechanical properties of the polymer obtained are summarized in
Table 1. The lightness L * is 53.2.
Example 1a
[0166] The polyester from Example 1 is used in a solid-state
post-condensation step. First, the polymer is crystallized for 2 h
in an oven under vacuum at 170.degree. C. The crystallized polymer
is then introduced into an oil bath rotavap fitted with a
cannulated flask. The granules are then subjected to a temperature
of 248.degree. C. and a nitrogen flow of 3.3 l/min.
[0167] After 23 h the polymer reaches a reduced viscosity in
solution of 106.5 ml/g. Finally, after 54 h of post-condensation,
the polymer will have a viscosity in solution of 121.3 ml/g. The
mechanical properties of the polymer obtained are summarized in
Table 1.
Example 1 b
[0168] According to another process according to the invention, the
polymer of Ex. 1 was extruded in a DSM twin-screw microextruder in
the presence of 1 w % carbonylbiscaprolactam (Allinco CBC). The
extrusion was carried out on 12 g of polymer for 2 min at
300.degree. C. The polymer has a viscosity in solution of 85.5
ml/g.
Example 2
[0169] 1432 g (9.9 mol) of 1,4-cyclohexanedimethanol, 484 g (3.3
mol) of isosorbide, 2000 g (12.0 mol) of terephthalic acid, 1.65 g
of Irganox 1010 (antioxidant) and 1.39 g of dibutyltin oxide
(catalyst) are added to a 7.5 I reactor. To extract the residual
oxygen from the isosorbide crystals, four vacuum-nitrogen cycles
are performed once the temperature of the reaction medium is
between 60 and 80.degree. C. The reaction mixture is then heated to
275.degree. C. (4.degree. C./min) under 6.6 bar of pressure and
with constant stirring (150 rpm). The degree of esterification is
estimated from the amount of distillate collected. The pressure is
then reduced to 0.7 mbar over 90 minutes following a logarithmic
ramp and the temperature is brought to 285.degree. C. These vacuum
and temperature conditions were maintained until an increase in
torque of 12.1 Nm relative to the initial torque was obtained.
Finally, a polymer rod is cast via the bottom valve of the reactor,
cooled to 15.degree. C. in a heat-regulated water bath and chopped
in the form of granules of about 15 mg.
[0170] The resin thus obtained has a reduced viscosity in solution
of 80.1 ml/g.sup.-1. .sup.1H NMR analysis of the polyester shows
that the final polyester contains 8.5 mol % of isosorbide relative
to all the monomer units. With regard to the thermal properties,
the polymer has a glass transition temperature of 96.degree. C., a
melting point of 253.degree. C. with an enthalpy of fusion of 23.2
J/g. The lightness L * is 55.3.
Example 2a
[0171] The polyester from Example 2 is used in a solid-state
post-condensation step. First, the polymer is crystallized for 2 h
in an oven under vacuum at 170.degree. C. The crystallized polymer
is then introduced into an oil bath rotavap fitted with a
cannulated flask. The granules are then subjected to a temperature
of 230.degree. C. and a nitrogen flow of 3.3 l/min.
[0172] After 31 h of post-condensation, the polymer will have a
viscosity in solution of 118.3 ml/g. The mechanical properties of
the polymer obtained are summarized in Table 1.
Example 2b
[0173] According to another process according to the invention, the
polymer of Ex. 2 was extruded in a DSM twin-screw microextruder in
the presence of 1 w % carbonylbiscaprolactam (Allinco CBC). The
extrusion was carried out on 12 g of polymer for 2 min at
300.degree. C. The polymer has a viscosity in solution of 92.8
ml/g.
Example 3
[0174] 1194 g (8.3 mol) of 1,4-cyclohexanedimethanol, 726 g (5.0
mol) of isosorbide, 2000 g (12.0 mol) of terephthalic acid, 1.65 g
of Irganox 1010 (antioxidant) and 1.39 g of dibutyltin oxide
(catalyst) are added to a 7.5 I reactor. To extract the residual
oxygen from the isosorbide crystals, four vacuum-nitrogen cycles
are performed once the temperature of the reaction medium is
between 60 and 80.degree. C. The reaction mixture is then heated to
275.degree. C. (4.degree. C./min) under 6.6 bar of pressure and
with constant stirring (150 rpm). The degree of esterification is
estimated from the amount of distillate collected. The pressure is
then reduced to 0.7 mbar over 90 minutes following a logarithmic
ramp and the temperature is brought to 285.degree. C. These vacuum
and temperature conditions were maintained until an increase in
torque of 11.1 Nm relative to the initial torque was obtained.
Finally, a polymer rod is cast via the bottom valve of the reactor,
cooled to 15.degree. C. in a heat-regulated water bath and chopped
in the form of granules of about 15 mg.
[0175] The resin thus obtained has a reduced viscosity in solution
of 66.2 ml/g.sup.-1. .sup.1H NMR analysis of the polyester shows
that the final polyester contains 15.1 mol % of isosorbide relative
to all the monomer units. With regard to the thermal properties
(measured at the second heating), the polymer has a glass
transition temperature of 109.degree. C. The lightness L* is
51.5.
Example 3a
[0176] The polyester from Example 3 is used in a solid-state
post-condensation step. First, the polymer is crystallized for 8 h
30 in an oven under vacuum at 170.degree. C. The crystallized
polymer is then introduced into an oil bath rotavap fitted with a
cannulated flask. The granules are then subjected to a temperature
of 210.degree. C. and a nitrogen flow of 3.3 l/min.
[0177] After 33 h of post-condensation, the polymer will have a
viscosity in solution of 94.2 ml/g. The mechanical properties of
the polymer obtained are summarized in Table 1.
Example 3b
[0178] According to another process according to the invention, the
polymer of Ex. 2 was extruded in a DSM twin-screw microextruder in
the presence of 1 w % carbonylbiscaprolactam (Allinco CBC). The
extrusion was carried out on 12 g of polymer for 2 min at
300.degree. C. The polymer has a viscosity in solution of 85.4
ml/g.
Counter-example 1
[0179] This example was carried out according to the embodiment
recommended by patent application US 2012/0177854 A1.
[0180] 3038 g (21.0 mol) of 1,4-cyclohexanedimethanol, 440 g (3.0
mol) of isosorbide, 2000 g (12.0 mol) of terephthalic acid, and
0.38 g of germanium dioxide are added to a 7.5 I reactor. To
extract the residual oxygen from the isosorbide crystals, four
vacuum-nitrogen cycles are performed once the temperature of the
reaction medium is between 60 and 80.degree. C. The reaction
mixture is then heated to 250.degree. C. (4.degree. C./min) under
6.6 bar of pressure and with constant stirring (150 rpm). The
degree of esterification is estimated from the amount of distillate
collected. The pressure is then reduced to 0.7 mbar over 90 minutes
following a logarithmic ramp and the temperature is brought to
280.degree. C. These vacuum and temperature conditions were
maintained for 210 minutes without obtaining an increase in torque.
The casting of the reactor did not make it possible to extrude a
rod of polymer in order to carry out the granulation thereof.
[0181] The resin thus obtained had a reduced viscosity in solution
of 16.4 ml/g.sup.-1 under the conditions as defined in the present
invention, that is to say a much lower viscosity than that of the
polymer according to the invention. This polymer exhibits
insufficient properties to be able to evaluate its mechanical
properties.
Counter-example 2
[0182] 859 g (13.8 mol) of ethylene glycol, 546 g (3.7 mol) of
isosorbide, 2656 g (16.0 mol) of terephthalic acid, 1.65 g of
Irganox 1010 (antioxidant) and 1.39 g of dibutyltin oxide
(catalyst) are added to a 7.5 I reactor. To extract the residual
oxygen from the isosorbide crystals, four vacuum-nitrogen cycles
are performed once the temperature of the reaction medium is
between 60 and 80.degree. C. The reaction mixture is then heated to
275.degree. C. (4.degree. C./min) under 6.6 bar of pressure and
with constant stirring (150 rpm). The degree of esterification is
estimated from the amount of distillate collected. The pressure is
then reduced to 0.7 mbar over 90 minutes following a logarithmic
ramp and the temperature is brought to 285.degree. C. These vacuum
and temperature conditions were maintained until an increase in
torque of 15.0 Nm relative to the initial torque was obtained.
Finally, a polymer rod is cast via the bottom valve of the reactor,
cooled to 15.degree. C. in a heat-regulated water bath and chopped
in the form of granules of about 15 mg.
[0183] The resin thus obtained has a reduced viscosity in solution
of 58.8 ml/g.sup.-1. .sup.1H NMR analysis of the polyester shows
that the final polyester contains 8.7 mol % of isosorbide relative
to all the monomer units. With regard to the thermal properties
(measured at the second heating), the polymer has a glass
transition temperature of 97.degree. C. The lightness L* is
46.2.
[0184] This sample does not exhibit sufficient crystallinity or a
sufficient crystallization rate to allow a solid-state
post-condensation step to be carried out (it has a zero heat of
fusion after heat treatment for 10 hours at 170.degree. C.).
TABLE-US-00001 TABLE 1 Mechanical properties Impact strength
(KJ/m.sup.2) Without Notched Notched Flexural Traction Tensile
notch at 2 mm at 2 mm at Modulus Modulus strength Deformation Shore
D 25.degree. C. 25.degree. C. -30.degree. C. (MPa) (MPa) (MPa) at
break (%) Vicat HDT hardness Ex1 No 10 NM 1512 711 36 247 100 84 76
breaking (>155) Ex. 1a No No 23 1459 736 43 200 100 88 77
breaking breaking (>155) (>155) Ex. 2a No No 22 1523 760 44
203 107 95 81 breaking breaking (>155) (>155) Ex. 3a No No 19
1608 798 40 164 115 103 81 breaking breaking (>155) (>155)
C-Ex. 2 9.6 NM NM 2400 1110 39 4 96 86 81 Tritan No 94 NM 1480.9
44.7 147.4 117.9 103.8 79 TX2001 breaking (>155)
Conclusions from Tests
[0185] The comparative polyester 1, which is that described in the
application US 2012/0177854 A1, has a very low viscosity, in
comparison with the polyester according to the invention of example
1. These two examples show that, surprisingly, it is entirely
possible to form viscous polymers using the process of the first
variant of the invention.
[0186] The polyesters according to the invention, produced under
the same conditions as the comparative polyester of counter-example
2 (polyester further comprising a linear aliphatic diol) have lower
coloration and also far superior impact strength properties.
[0187] The polyesters according to the invention have a high
viscosity or even a very high viscosity when a step of increasing
the molar mass by SSP or reactive extrusion is carried out.
[0188] The semi-crystalline polyesters, the molar mass of which was
increased by SSP, have a higher viscosity than that of the
polyesters the molar mass of which was increased by reactive
extrusion,
[0189] The very high-viscosity polyesters have excellent impact
strength, at room temperature and in cold conditions.
[0190] The polyesters according to the invention have excellent
mechanical properties, similar to the Tritan .TM. type performance
copolyesters sold by Eastman.RTM.. Their impact strength properties
are even better.
* * * * *